Related papers: Gate-tuned Superconductor-Insulator transition in …
We report $^{75}$As nuclear magnetic resonance (NMR) / nuclear quadrupole resonance (NQR) and transmission electron microscopy (TEM) studies on LaFeAsO$_{1-x}$F$_{x}$. There are two superconducting domes in this material. The first one…
Because the cuprate superconductors are doped Mott insulators, it would be advantageous to solve even a toy model that exhibits both Mottness and superconductivity. We consider the Hatsugai-Kohmoto model, an exactly solvable system that is…
The single-layer FeSe/SrTiO3 (FeSe/STO) films have attracted much attention because of their simple crystal structure, distinct electronic structure and record high superconducting transition temperature (Tc). The origin of the dramatic Tc…
Realizing an excitonic insulator phase from narrow-gap semiconductors remains challenging, as unambiguous experimental signatures are difficult to establish. Ta$_2$NiSe$_5$ has been widely regarded as a leading candidate, yet the nature of…
While the search of high Tc superconductivity was driven mostly by trial and error methodology searching for novel materials, here we provide a quasi-first-principle quantum theory for engineering superconductivity in artificial high-Tc…
Ionic gating is a very popular tool to investigate and control the electric charge transport and electronic ground state in a wide variety of different materials. This is due to its capability to induce large modulations of the surface…
We report an NMR investigation of the superconductivity in BaFe(2)As(2) induced by Co doping (Tc=22K). We demonstrate that Co atoms form an alloy with Fe atoms and donate carriers without creating localized moments. Our finding strongly…
We report a $^{73}$Ge nuclear-quadrupole-resonance (NQR) study on novel evolution of unconventional superconductivity in antiferromagnetic (AFM) CeNiGe$_3$. The measurements of the $^{73}$Ge-NQR spectrum and the nuclear spin-lattice…
Strongly correlated materials often undergo a Mott metal-insulator transition, which is tipically first-order, as a function of control parameters like pressure. Upon doping, rich phase diagrams with competing instabilities are found. Yet,…
We investigate the magnetic phase diagram of the newly discovered iron-based high temperature oxypnictide superconductors of the type RO$_{1-x}$F$_x $FeAs, with rare earths R=La, Sm, Nd, Pr and Ce by means of {\it ab initio} SGGA and SGGA+U…
We use ionic liquid-assisted electric field effect to tune the carrier density in an electron-doped cuprate ultrathin film and cause a two-dimensional superconductor-insulator transition (SIT). The low upper critical field in this system…
Many recent studies show that superconductivity not only exists in atomically thin monolayers but can exhibit enhanced properties such as higher transition temperature and stronger critical field. Nevertheless, besides being air unstable,…
The magnetic moment of a quantum dot can be screened by its coupling to a superconducting reservoir, depending on the hierarchy of the superconducting gap and the relevant Kondo scale. This screening-unscreening transition can be driven by…
We investigate superconductivity and transport properties of Co doped SmFe$_{1-x}$Co$_{x}$AsO system. The antiferromagnetic (AFM) spin-density wave (SDW) order is rapidly suppressed by Co doping, and superconductivity emerges as $x$ $\geq$…
The mechanism of -U center formation in high-$T_{c}$ superconductors (HTS) with doping is considered. It is shown that the transition of HTS from insulator to metal passes through the particular dopant concentration range where the local…
Interfacial superconductivity has manifested itself in various types of heterostructures: band insulator-band insulator, band insulator-Mott insulator, and Mott insulator-metal. We report the observation of high-temperature…
BaFe$_2$S$_3$ is a quasi one-dimensional Mott insulator that orders antiferromagnetically below 117(5)\,K. The application of pressure induces a transition to a metallic state, and superconductivity emerges. The evolution of the magnetic…
The superfluid-Mott insulator transition of spin-2 boson atoms with repulsive interaction in an optical lattice in a magnetic field is presented. By using the mean field theory, Mott ground states and phase diagrams of superfluid-Mott…
To realize room temperature ferromagnetic (FM) semiconductors is still a challenge in spintronics. Many antiferromagnetic (AFM) insulators and semiconductors with high Neel temperature $T_N$ are obtained in experiments, such as LaFeO$_3$,…
The detailed structure of the $T \times doping$ phase diagram of hole doped High-Tc superconducting cuprates is investigated from the perspective of a recently proposed comprehensive theory for these materials. Our theory is compared to…